1. Field of the Invention
This invention relates to a telephone answering device, and more particularly to a telephone answering device capable of answering a third party caller on a second telephone line.
2. Background of Related Art
Telephone answering devices (TADs) (i.e., answering machines) are useful devices for the home or small office. A conventional TAD operates on a single telephone line and answers an incoming call to an unused (i.e., on-hook) telephone after a desired number of rings. The TAD causes the telephone line to enter an off-hook condition, then plays an outgoing message (OGM) to the caller. After the OGM, the caller may leave a voice message on the TAD. At a later time the voice message is replayed by the user, either local to the TAD or via remote connection from another telephone.
Unfortunately, a conventional TAD has limited usefulness when the user is already on the telephone. When the telephone line is already in an off-hook condition and in use between the user and a first caller, any incoming third party calls will be unsuccessful and receive a busy signal from the telephone company. Thus, the third party caller must continue to dial the telephone number of the user until such time as the telephone line is back in an on-hook condition.
FIG. 5 shows a conventional TAD capable of answering an incoming call on a telephone line. In FIG. 5, a TAD 11 is connected to a telephone company central office 13 via a telephone line 14. A telephone line interface (TLI) 48 in the TAD 11 provides the conventional isolation, DC and AC impedance as required by telephone company standards. The TLI 48 also provides a ring detect signal to a controller 18. Controller 18 may be any suitable processor, e.g., microprocessor, microcontroller, or digital signal processor (DSP). The ring detect signal indicates to the controller 18 the ringing of an incoming call on the telephone line 14.
After a desired number of ring signals, the TAD 11 causes the TLI 48 to place the telephone line in an off-hook state, and instructs a voice recorder/playback audio module 20 to play an outgoing message (OGM) on the telephone line 14 to the caller. Upon completion of the OGM, the caller may leave a voice message in voice memory 21 under the control of controller 18. A keypad 26 allows the user to select various modes of operation, including the playback of voice messages.
Services providing call related information regarding a third party caller are useful to users of a telephone system, but fall short of solving the problem of conventional TAD systems which do not allow a third party caller to leave a voice message on a TAD. One well known and popular call information service provided in the United States is Calling Identity Delivery (Caller ID). This service typically provides the telephone number and household name information of a calling party to the called party before the call is answered. Basic call information such as Caller ID information is transmitted from the local telephone company to the called party while the called party""s phone is in a hung-up or on-hook state, e.g., between the first and second rings. Based on a display of the call related information, the called party may decide not to answer the incoming call and instead allow the TAD to record a voice message from the caller. The conventional TAD 11 shown in FIG. 5 includes a Caller ID detector/receiver 12 to detect and receive the telephone number and/or household name of a calling party, which is displayed on display 28.
Another telephone company service which has become well known and popular is that which allows a third party to call while the called party is already off-hook, currently known in the United States as Call Waiting. Call Waiting allows someone who is already using the telephone (i.e., in an off-hook state), to receive an audible interruption, click or other indication at the customer premises equipment that another person is calling, and then to establish a connection with the third party caller as desired by placing the first party on hold.
More recently, call information has been combined with third party caller services to provide an advanced service currently known as Calling Identity Delivery on Call Waiting (CIDCW) in the United States. CIDCW service allows a customer, while off-hook on an existing call, to receive information about an incoming calling party on a waited call before answering that incoming call waiting call. Transmission of the third party""s call information with this service takes place almost immediately after the customer premises equipment (CPE) is alerted to the new call with a CPE Alerting Signal (CAS). The CAS is a short burst of a combination of high frequencies that are appended to the Subscriber Alerting Signal (SAS) otherwise known as the xe2x80x9cCall Waiting Tonexe2x80x9d. Using CIDCW, a user can decide whether or not to answer a third party incoming call waiting call. If the third party call is not answered, there is no ability for the third party caller to leave a voice message with the user via the dialed number.
Customer premises equipment capable of receiving on-hook call information such as Caller ID (CID) including Calling Number Delivery (CND) and Calling Name Delivery (CNAM), is generally referred to as Type 1 customer premises equipment. Customer premises equipment additionally capable of receiving call information when off-hook or already in an established call with another party (CIDCW) is generally referred to as a Type 2 customer premises equipment. With Type 2 customer premises equipment and Caller ID service, the called party is alerted to the availability of call information for an incoming call waiting call with an alerting CAS tone. The alerting CAS tone is acknowledged with a DTMFD, and the FSK data corresponding to the call information follows from the central office to the customer premises equipment.
At any time after a called party having CIDCW service has been alerted to the availability of call information for an incoming call waiting call and while a party is still in the waited state, CIDCW allows the customer to flash the switch hook to retrieve the waited call while placing the first caller on hold, and subsequently to go back and forth between the current far-end party and the held party by flashing. CIDCW provides all the capabilities associated with the current CW service, with the additional capability of providing CID data to a customer on waited calls. Therefore, CIDCW is considered an enhancement of the CW service. A telephone line may either have call waiting (CW) or CIDCW service enabled, but not both at the same time.
Thus, CID is a service which provides display data for a user of a telephone to make a decision as to whether or not to answer an incoming call, and if not to let the TAD answer the call. However, there is no provision in CIDCW service to allow the third party caller to leave a voice message on a TAD at the user""s premises. Thus, CIDCW service is not conventionally applicable for use with a TAD.
There is a need for a TAD which is capable of allowing a third party caller to leave a voice message at a called party""s TAD without requiring a user to hang up on an existing call.
In accordance with the principles of the present invention, a telephone answering device comprises a processor, a voice recorder/playback module, a call related information detector/receiver, an automatic callback module, and a first telephone line interface. A DTMF generator automatically dials a telephone number based on information received by the call information detector/receiver.
The present invention further provides methods for automatically calling back a third party caller from a telephone answering device. In one method, a first telephone call is established on a first telephone line with customer premises equipment. An indication of call related information with respect to a third party caller is received, and the call related information is stored for access by the telephone answering device. Then, a callback is initiated to the third party caller from the telephone answering device based on the stored call related information.
In another method, a plurality of predetermined call related information is stored in a telephone answering device. A first telephone call is established on a first telephone line with customer premises equipment. Thereafter, indication is received relating to call related information with respect to a third party caller on a second telephone line. The call related information with respect to said third party caller is compared to the pre-stored call related information, and if a match is found, the third party caller on the second telephone line is automatically answered.